ShiftedParticleProducer.cc

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#include "PhysicsTools/PatUtils/plugins/ShiftedParticleProducer.h"
#include "FWCore/Utilities/interface/isFinite.h"

ShiftedParticleProducer::ShiftedParticleProducer(const edm::ParameterSet& cfg)
{
  moduleLabel_=cfg.getParameter<std::string>("@module_label");
  srcToken_ = consumes<CandidateView>(cfg.getParameter<edm::InputTag>("src"));
  shiftBy_ = cfg.getParameter<double>("shiftBy");

  if ( cfg.exists("binning") ) {
    typedef std::vector<edm::ParameterSet> vParameterSet;
    vParameterSet cfgBinning = cfg.getParameter<vParameterSet>("binning");
    for ( vParameterSet::const_iterator cfgBinningEntry = cfgBinning.begin();
      cfgBinningEntry != cfgBinning.end(); ++cfgBinningEntry ) {
      binning_.push_back(new binningEntryType(*cfgBinningEntry,moduleLabel_));
    }
  } else {
    std::string uncertainty = cfg.getParameter<std::string>("uncertainty");
    binning_.push_back(new binningEntryType(uncertainty, moduleLabel_));
  }

  produces<reco::CandidateCollection>();
}

ShiftedParticleProducer::~ShiftedParticleProducer()
{
  for(std::vector<binningEntryType*>::const_iterator it = binning_.begin();
    it != binning_.end(); ++it ) {
    delete (*it);
  }
}

void 
ShiftedParticleProducer::produce(edm::Event& evt, const edm::EventSetup& es)
{
  edm::Handle<CandidateView> originalParticles;
  evt.getByToken(srcToken_, originalParticles);

  std::auto_ptr<reco::CandidateCollection> shiftedParticles(new reco::CandidateCollection);

  for(CandidateView::const_iterator originalParticle = originalParticles->begin();
      originalParticle != originalParticles->end(); ++originalParticle ) {
    
    double uncertainty = getUncShift(originalParticle);
    double shift = shiftBy_*uncertainty;

    reco::Candidate::LorentzVector shiftedParticleP4 = originalParticle->p4();
    //leave 0*nan = 0
    if (! (edm::isNotFinite(shift) && shiftedParticleP4.mag2()==0)) shiftedParticleP4 *= (1. + shift);

    std::auto_ptr<reco::Candidate> shiftedParticle( new reco::LeafCandidate( *originalParticle ) );
    shiftedParticle->setP4(shiftedParticleP4);
    
    shiftedParticles->push_back( shiftedParticle.release() );
  }

  evt.put(shiftedParticles);
}

double 
ShiftedParticleProducer::getUncShift(const edm::View<reco::Candidate>::const_iterator& originalParticle) {
  double valx=0;
  double valy=0;
  for(std::vector<binningEntryType*>::iterator binningEntry=binning_.begin();
      binningEntry!=binning_.end(); ++binningEntry ) {
    if( (!(*binningEntry)->binSelection_) || (*(*binningEntry)->binSelection_)(*originalParticle) ) {

      if( (*binningEntry)->energyDep_ ) valx=originalParticle->energy();
      else valx=originalParticle->pt();

      valy=originalParticle->eta();
      return (*binningEntry)->binUncFormula_->Eval(valx, valy);
    }
  }
  return 0;
}

#include "FWCore/Framework/interface/MakerMacros.h"
DEFINE_FWK_MODULE(ShiftedParticleProducer);